Field of the Invention
The present invention relates to a method for adjusting the volume of the combustion chamber of an engine.
Description of the Related Art
The volume of a combustion chamber in an automobile engine greatly influences the combustion characteristics of fuel and the performance of the engine. Making the volume of the combustion chamber fall within a predetermined range is therefore necessary. More specifically, the volume of the recess of a cylinder head constituting part of the combustion chamber is measured, and a mating surface for a cylinder block or the recess is machined in accordance with the measurement result. By this machining process, the volume of the combustion chamber can be adjusted.
As a conventional method of obtaining the volume of the recess of the cylinder head, a method of filling the valve hole of a cast cylinder head with clay or the like, pouring kerosene into the recess of the cylinder head, and obtaining the volume of the recess from the volume of the kerosene is often used. However, this method is inefficient because of the intervention of manual work.
Japanese Patent Laid-Open No. 2011-256730 discloses a technique of, when forming a cylinder head by casting, setting a flat reference surface at the top of the recess of the cylinder head, and measuring a distance between the mating surface and the reference surface to decide a cutting amount.
However, the method described in the above literature only measures the distance between one point of the reference surface and the mating surface, so the accuracy is not so high.